>
>For your info, my client have web hosting.
>
>Please advice. Thank you

The real hurdle you have is communications... you need to determine whether you need 'real time' connectivity or not. I would say that there should be one 'central' server that is updated at a specific interval by all stores that any single store can call to check inventory when needed. This can all be done with a modem connection - or if you have high speed connectivity at each store, the process will go much smoother.

You could also have a webservice at the central server if you have web server.

The options are only dependant on your clients needs and the amount of money they are willing to spend.